Improvement in piano-fortes



C. H. L. PLASS. Pianoforte.

No. 210,223. Patented Nov. 26.1878.

UNTTED STATES PATENT OEEIcE.

CARL I-I. L. PLASS, OF HAMBURG, GER-MANY.

IMPROVEMENT IN PIANO-FORTES.

Specification tin-ming part of Letters Patent No. 210.223, dated November QG, 1.378;

application tiled Jury 29, 187s.

To all whom it may concern:

Be it known that I, CARL HEINRICH LUD- WIG PLAss, ot` Ilamburg, Germany, have inventedImprovements inliano-Fortcs, ofwhich which the following is a specification:

rIhe objects ot' my invention are, irst, to support each hammer upon a helical spring, which is secured to the hammer-butt by a screw, the free end of the spring taking into a recess in the upper end ot' the hopper, in order that very rapid movements of the hammers may be communicated from the keys.

The improvements hereinbet'ore referred to are clearly shown in the accompanying drawings, in which* Figure l represents in detail my spring and screw, and Fig. 2 their position in a complete action as ittcd to a horizontal instrument.

A is the key; B, the pivot or pin, on which it moves when pressed upon by the linger ot' an operator. C is thejack, to which the hop per D is hinged or jointed at a. This hopperstick has a tail-piece, b, between which and a projection, c, ot' the jack a helical or spiral spring, d, is fitted to force the nose c of the hopper-stick into the notch h under the butt or tail-piece F of the hammer G each time the hammer falls after striking its string or wire Il. rlhe tail-piece F of the hammer is hung or pivoted to the rail I in the usual manner; but it has within the body of it a screw-nut, J, through which ascrew-pin, K, passes. The lower end ot this pin has attached a helical or a spiral spring, f, whose opposite end being tit-ted with a leather pad bears in a recess formed in the top ofthe hopper. This screwpin and spring form an important portion of this invention, as by their combination with -thc hopper, which has to execute a short movement only, blows of the hammer on the string or wire are produced most powerful or .very sott, and with almost unlimited quiekness, when and depending upon the manner in which the key is acted upon. By turning the screw-pin K more or less, the desired strength can be easily given to the spring, which is of very great advantage, especially should the spring become weak by heavy or long use.

The same amount and volume of sound, as above mentioned, is, by the action of the spring, produced when the key A, having been pressed down completely, is lifted a short distance only and acted upon again, leaving nothing tobe desired as regards clearness ot' sound.

Through a projection, 11", at the back of the hammer-rest L a screw-pin, g, is passed, its lower end having a pad or buffer, j, upon it to receive the back part of the key when acted upon. By turning' this screw-pin more or less the movements which the key has to execute are regulated with the utmost ease and certainty.

In the front projection k of the hammer-rest L a screw-pin, l, is passed, whose lower endis iitted with a pad or buffer, m, to be brought more or less close to the tail-piece b of the hopper D to draw the nose c of the hopper. stick out of the notch it after havinglifted the hammer G, so that in that position the hopper brings the spring fin its full action, and consequent] y keeps the hammer close to the spring or wire II. By turning the screw-pin K more or less the hammer can be held at any suitable distance from the string or wire.

The regulation of the keys, so as to adjust them as regards the different weights of the hammers inthe higher and lower octavos, is effected by plugging' the front parts only of the keys with lead. They need not, therefore, be plugged in the back part, because they get the full weight of the hammers, which causes a considerable fall of the back part of the keys.

The hammer-rest L (shown in the drawing, Fig. 2) is only to support the hammer after the key is removed, which can be done by lifting it oit' the pin, the jack C, the hopper D, and and the sticker N going with it.

The damper M is of ordinar t construction, and the parts N O P also.

It will be observed by the drawing, Fig. l, that the working parts ol the action move upon two centers, a and n, only.

In fitting the invention to an upright piano, (see Fig. 3,) the serew-pin K in the butt F ot' the hammer G has attached the helical or spiral spring j', as explained for Fig. 1. In this upright action, the hopper stick D is jointed to a stud on a horizontal piece, C, the front end p of which carries a rod, q, for operating the demper M by 2in upward circular movement through its Connection Wit-h links It S from the damper-rail T, the dampenpud or cushion being thus brought to not upon the spring H to damp it at about the spot at which it had been previously struck by the hammer G. The horizontal piece C rests upon the jack C, and is acted upon by the key A.

By hanging the damper M in the manner described und shown, the vibrations of :I string are stopped with greater certainty and with more uniformity.

I claim as my invention- The combination, in :t piano-forte, lbSfHltiztlly as described, of adhelicstl spring between the hopper-stick and the hammer-butt, seid butt having :t screw-pin for regulating the spring-pressure.

CARL HEINRICH LUDWIG PLAss.

Witnesses:

JOHN MARTIN EMIL COLLINS, HEINRICH FRIEDERICH SoNNnBoRN 

